This invention relates to a gasoline injector for supplying fuel to an air inlet of a spark ignition engine, the injector being of the type comprising a central hollow magnetic core member having one end connected in use to a source of fuel, a hollow body formed from magnetic material and surrounding the core member in spaced relationship, the body defining an annular pole face which extends inwardly towards the other end of the core member, the end face of the core member defining a further pole face, a winding which in use can be energized to cause the pole faces to assume opposite magnetic polarity, a seat member spaced from said pole faces, the seat member defining an outlet orifice, a plate-like valve member formed from magnetic material located with clearance between the seat member and the pole faces and resilient means acting on said valve member to urge the valve member into contact with the seat member, the valve member being lifted from the seat member by magnetic forces when the winding is energized, to allow fuel flow through the outlet orifice.
An injector of the aforesaid type is known from British Pat. No. 2147949B in which a non-magnetic spacer is provided which is positioned to prevent metal-to-metal contact of the valve member and the pole face defined by the body thereby minimizing the risk of the valve member sticking to the pole face due to residual magnetism. While sticking due to magnetic effects is prevented by the spacer the valve member does tend to adhere to the spacer due to the fact that the spacer and valve member are wetted by the gasolene thereby slowing the closure of the valve member. If a stronger spring is provided to return the valve member more quickly into contact with the seat member, the magnetic force required to lift the valve member away from the seat member will be increased and as a result the power consumption of the injector will be increased.